For adult fiction and nonfiction, ebooks provided $1.3-billion in revenue, a 33 percent gain.

London - They have been one of the retail sensations of the Christmas season.

Sales of eReaders, the handheld devices on to which electronic books can be downloaded, rocketed through December.

It is good news for makers such as Amazon, which produces the best- selling Kindle and collects 30 percent of the price of downloaded books.

But there are fears that their profits could be hit by a wave of pirate eBooks available to download for free.

Just as pirates and websites including Napster undermined the music industry by putting music on the web for free, so the same is now happening with eBooks.

Creating pirate copies of published books is simple and can be done using a computer and a scanner in a relatively short period of time.

The pirates have developed software which people can download to their home computers to convert these pages into images that can be read on a Kindle or similar device.

One pirate website boasts: “With a Kindle there is pretty much no protection against pirated books. There are programs which can simply convert any piece of text into the proper format and it will show on your Kindle as if you had bought it!”

It is estimated that up to 20 percent of eBook downloads are from pirate sites. The Publishers Association issued 115,000 legal threats to websites to stop them offering free pirated books in 2011, a rise of 130 percent on 2010.

Publishers are in talks with the Government and Google to find ways to combat the trade, which breaches their copyright.

They have asked Google to demote pirate websites to ensure they do not appear at the top of web searches for consumers looking to find free eBooks. Pressure is also being put on internet service providers to shut down pirate websites.

One of the best-known eBook pirate websites offers a selection of best-sellers that should not yet even be available to the public.

One example is 77 Shadow Street, the new novel by Dean Koontz. Amazon customers will have to pay £11.96 (about R150) to pre-order it - but an eBook and audiobook version are already available for free from the pirate site.

The rise of the pirate eBook websites coincides with concern among consumers about the high price of legal book downloads.

Five big publishers, together with Apple, are under investigation by the European Commission for allegedly colluding to push up the price of eBooks by as much as 50 percent.

Many eBooks are available for as little as 99p, however a bestseller can cost more than £10.

In some cases, Amazon and Apple are charging more for an eBook download than the real book. - Daily Mail